C6X: early boot code
Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>
This patch provides the early boot code for C6X architecture. There is a
16 entry vector table which is used to direct reset and interrupt events. The
vector table entries contain a small amount of code (maximum of 8 opcodes)
which simply branches to the actual event handling code.
The head.S code simply clears BSS, setups up a few control registers, and calls
machine_init followed by start_kernel. The machine_init code in setup.c does
the early flat tree parsing (memory, commandline, etc). At setup_arch time, the
code does the usual memory setup and minimally scans the devicetree for any
needed information.
Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/c6x/kernel/head.S b/arch/c6x/kernel/head.S
new file mode 100644
index 0000000..133eab6
--- /dev/null
+++ b/arch/c6x/kernel/head.S
@@ -0,0 +1,84 @@
+;
+; Port on Texas Instruments TMS320C6x architecture
+;
+; Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
+; Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
+;
+; This program is free software; you can redistribute it and/or modify
+; it under the terms of the GNU General Public License version 2 as
+; published by the Free Software Foundation.
+;
+#include <linux/linkage.h>
+#include <linux/of_fdt.h>
+#include <asm/asm-offsets.h>
+
+ __HEAD
+ENTRY(_c_int00)
+ ;; Save magic and pointer
+ MV .S1 A4,A10
+ MV .S2 B4,B10
+ MVKL .S2 __bss_start,B5
+ MVKH .S2 __bss_start,B5
+ MVKL .S2 __bss_stop,B6
+ MVKH .S2 __bss_stop,B6
+ SUB .L2 B6,B5,B6 ; bss size
+
+ ;; Set the stack pointer
+ MVKL .S2 current_ksp,B0
+ MVKH .S2 current_ksp,B0
+ LDW .D2T2 *B0,B15
+
+ ;; clear bss
+ SHR .S2 B6,3,B0 ; number of dwords to clear
+ ZERO .L2 B13
+ ZERO .L2 B12
+bss_loop:
+ BDEC .S2 bss_loop,B0
+ NOP 3
+ CMPLT .L2 B0,0,B1
+ [!B1] STDW .D2T2 B13:B12,*B5++[1]
+
+ NOP 4
+ AND .D2 ~7,B15,B15
+
+ ;; Clear GIE and PGIE
+ MVC .S2 CSR,B2
+ CLR .S2 B2,0,1,B2
+ MVC .S2 B2,CSR
+ MVC .S2 TSR,B2
+ CLR .S2 B2,0,1,B2
+ MVC .S2 B2,TSR
+ MVC .S2 ITSR,B2
+ CLR .S2 B2,0,1,B2
+ MVC .S2 B2,ITSR
+ MVC .S2 NTSR,B2
+ CLR .S2 B2,0,1,B2
+ MVC .S2 B2,NTSR
+
+ ;; pass DTB pointer to machine_init (or zero if none)
+ MVKL .S1 OF_DT_HEADER,A0
+ MVKH .S1 OF_DT_HEADER,A0
+ CMPEQ .L1 A10,A0,A0
+ [A0] MV .S1X B10,A4
+ [!A0] MVK .S1 0,A4
+
+#ifdef CONFIG_C6X_BIG_KERNEL
+ MVKL .S1 machine_init,A0
+ MVKH .S1 machine_init,A0
+ B .S2X A0
+ ADDKPC .S2 0f,B3,4
+0:
+#else
+ CALLP .S2 machine_init,B3
+#endif
+
+ ;; Jump to Linux init
+#ifdef CONFIG_C6X_BIG_KERNEL
+ MVKL .S1 start_kernel,A0
+ MVKH .S1 start_kernel,A0
+ B .S2X A0
+#else
+ B .S2 start_kernel
+#endif
+ NOP 5
+L1: BNOP .S2 L1,5